The Effect of Environmental Conditions on Pollution Deposition and Canopy Leaching in Two Pine Stands (West Pomerania and Świętokrzyskie Mountains, Poland)

This study analyzed the effect of atmospheric deposition on canopy leaching processes in stands predominantly composed of Scots pines. The research was conducted in two stands: the first located in the southwestern part of the Świętokrzyskie Mountains in the area known as Białe Zagłębie (Malik), and the second in the northwestern part of Poland in Western Pomerania (Czarne). The study was conducted in the hydrological years 2010–2013. The goal of the study was to assess the chemical transformation of precipitation as a result of various human activities. In Malik, the main factor that determined the physicochemical and chemical properties of throughfall was the cement/lime dust emitted by nearby industrial plants, which not only affected the quantity of deposit but also contributed to the alkalization process of throughfall. By contrast, the main source of pollution in Czarne, where local emitters are absent, was long-distance transport. We conducted a principal component analysis (PCA) in both stands that produced components representing local pollution (Malik) and long-distance transport (Czarne). For the stand in Czarne, sea aerosols were an important source of Na+ and Cl− ions in precipitation. In both stands, the highest enrichment ratio (ER) values were recorded for K+ ions. The contribution of leaching processes to the bulk deposition of K+ ions in Malik was 85.8%, whereas in Czarne, it was 73.8%. Regardless of the degree of anthropopressure, the intensity of quantitative and qualitative transformation in pine stands was comparable.

Changes in the Physical Properties of Precipitation in Pine Stands in the Area with A Low Degree of Air Pollution (Western Pomerania)

The study presents the results of research conducted in the years 2010-2012 in pine stands in Western Pomerania. The research included physicochemical properties of bulk precipitation and throughfall. The results confirm that despite a decrease in the total throughfall in the interception process, the size of mineral and organic depositions in pine stands exceeded values recorded for bulk precipitation. It was caused both by the process of enriching the throughfall with (K+, Mg2+) rinsed out of needles and leaves and by washing off the dry deposition (NH4+, Cl-, Na+, SO42-, NO3 -). The share of leaching processes for K+ was 74.1%, while for Mg2+ 23.6% of the total load of these elements brought to the ground with throughfall. In the case of Ca2+ no canopy leaching was observed for this element. The throughfall acidification processes were mostly caused by NO3-.

Seasonal variation in throughfall and stemflow chemistry beneath a European beech (Fagus sylvatica) tree in relation to canopy phenology

The effect of canopy phenology on major ion fluxes beneath a mature European beech ( Fagus sylvatica L.) tree is examined. Annual and seasonal ion fluxes to the forest floor were significantly higher than the incoming wet-only deposition for all ions measured other than H+. The annual throughfall to wet deposition ratio generally ranged from 2.1 to 4.8. Stemflow contributed 9%–19% of the ion input to the forest floor, except for H+. Throughfall enrichment of K+, Ca2+, Mg2+, and NO3– was significantly higher in the leafed than in the leafless season, in contrast to Na+, NH4+, and H+. The temporal pattern of ion enrichment indicated canopy release of K+, Ca2+, and Mg2+ throughout the leafed season, of Na+, Cl–, and NH4+ from emerging leaves, and of Cl– and SO42– from senescing leaves. The contribution of canopy leaching to annual net throughfall and stemflow was estimated at 96% (K+), 54% (Ca2+), 40% (Mg2+), 12% (Cl–), and 7% (Na+, SO42–). Dry deposition accounted for 58%–75% of the total deposition onto the canopy. The throughfall enrichment during the leafless season indicated high particulate and gaseous dry deposition onto the woody canopy as well as K+ release from European beech branches.